This invention relates to an assembly for automatically compensating variations in the spacing between first and second structural members due to manufacturing and/or mounting tolerances.
A vast number of assemblies for compensating variations in the spacing between structural members has become known. There has become known also assemblies which allow for automatic compensation of spacing variations, i.e. without any additional action of an operator, in order not to increase the time for assembly. Such assemblies are shown for example in the German patent application DE 100 04 697 A1 and in the European patent applications EP 0 176 663 A1 and EP 0 848 168 A1. All these assemblies are relatively complex in that they require a relatively large number of components resulting in relatively high manufacturing and mounting costs.
The German patent application DE 199 49 654 A1 discloses an assembly for compensating spacing variations, which comprises an compensating element which consists of internal and external threaded sleeves adapted to be threadingly engaged with each other. The external threaded sleeve is fixed to a first structural member via an annular member. The internal threaded sleeve is designed so as to provide for frictional drag between the sleeve and bolt such that the bolt when threaded into the internal threaded sleeve causes the latter to rotate therewith. As a result thereof the bolt is xe2x80x9cunthreadedxe2x80x9d from the external threaded sleeve until the internal threaded sleeve engages the second structural member. The bolt can then be inserted through the internal threaded sleeve and secured by a nut which is supported against the second structural member. This compensating assembly therefore requires, additional to the bolt and nut, a pair of threaded sleeves and a threaded annular member so that it suffers from the drawbacks as set forth above. Since furthermore the nut has to be operated to be threadingly engaged by the bolt after the compensating operation has been terminated, the compensating operation is only partially automatic.
The European patent application EP 0 533 513 A1 discloses an assembly for compensating spacing variations, which consists of a bolt, a nut comprising a blind rivet nut, a compensation sleeve, and a counter-nut. The compensation sleeve has internal and external threads so that on the one hand the compensation sleeve can be threaded into the nut and on the other hand the bolt can be threaded into the compensation sleeve. For the compensation of spacing variations the compensation is sleeve is rotated by a manual tool so as to be axially moved in the nut until it engages the first structural member. Thereafter the compensation sleeve is manually secured by the counter-nut in order to clamp the two structural members together.
The assembly does not allow for automatic compensation of spacing variations apart from the fact that it also requires a substantial number of components.
It is a general object of the invention to provide an improved assembly for compensating variations in the spacing between first and second structural members due to manufacturing and/or mounting tolerances, which avoids the disadvantages of the prior assemblies while affording additional structural and operational advantages.
An important feature of the invention is the provision of an assembly which allows for automatic compensation of spacing variations, i.e. without any additional manual operation by an operator.
A further feature of the invention is the provision of an assembly of the type as set forth which is of relatively simple and economical construction.
A further feature of the invention is the provision of an assembly of the type as set forth which requires a minimal number of components.
The assembly of the present invention requires only a bolt, a nut and a compensation sleeve, while a washer for the head of the bolt may be provided additionally. The bolt, the nut and the compensation sleeve are designed such that they include a right-handed pair of threads and a left-handed pair of threads. Furthermore, the compensation sleeve includes a clamping portion adapted to frictionally engage the bolt so as to be rotatable thereby. As a result of these measures, the bolt when being rotated for mounting the assembly to the structural members, initially causes the compensation sleeve to rotate so as to be xe2x80x9cunthreadedxe2x80x9d from the nut until the compensation sleeve engages the first structural member. Thereafter, the bolt can be rotated relative to the compensation sleeve so as to threadingly engage the nut directly or indirectly in order to clamp the two structural members together.
The pairs of right-handed and left-handed threads and the frictional drag between the compensation sleeve and the bolt provide for an assembly which requires only a minimal number of components, while the compensating operation is performed automatically, i.e. without any additional manual operation by an operator. As a result thereof the assembly of the present invention is of extremely simple and economical construction.
The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention.